This invention relates to AM-FM broadband radio antennas and particularly to such antennas adapted for mounting in a motor vehicle windshield. Such antennas have become relatively popular on motor vehicles because of their inconspicuous nature and because they are not as vulnerable to vandalism as are whip antennas.
Although such antennas have been generally adequate for receiving AM broadcast signals, their performance with FM broadcast signals, and particularly with FM stereo signals, has been somewhat less satisfactory. With the growing popularity of FM stereo broadcast and the increasing number of vehicles equipped with radios capable of receiving FM stereo signals, a demand is growing for a windshield mounted broadband radio antenna offering improved FM performance.
On the other hand, one of the main advantages of the windshield mounted antenna as presently designed is its generally inconspicuous nature. FIG. 1 shows the general configuration of such antennas in present vehicle production; and it should be plain from FIG. 1 that the antenna elements have been placed in such a manner that they are not generally within the field of view of a vehicle driver or passenger and are thus not generally noticed. An antenna showing improved FM reception capability should still not be annoying or objectionable in appearance to a vehicle driver or passenger.